"We know that tens of thousands of people will have died over the last year ... Children will have suffered the most, malnutrition rates in Somalia were the highest in the world, and I think the highest recorded... up to 50 percent of the child population suffered from severe or acute malnutrition."

In July, the UN declared a famine in three parts of southern Somalia controlled by Al Shabaab. By September the famine had spread into another three areas of Somalia, and 750,000 people were affected, according to the UN High Commissioner for Refugees (UNHCR).

In November, with food aid beginning to reach Somalis and rainfall returning to East Africa, the UN downgraded the famine in some areas, and said that 250,000 people were now affected.

Malnutrition rates have started to drop, but the food crisis is expected to continue for the next six months, Bowden said.